1. Field of Invention
The present invention relates to a battery module.
2. Background Art
Flat and thin batteries (“flat batteries”) are known and used in the art. In flat batteries, power generating elements with cathode and anode electrode plates are sealed within a pocket-shaped outer cover made of a film member such as a laminate film. Plate-shaped electrode terminals, which are connected to the power generating elements sealed within the outer cover, project from the interior to the exterior of the outer cover. Japanese Laid-Open Patent Publication No. 2001-256934, which is herein incorporated by reference in its entirety, discloses a high power and high capacity battery module in which a plurality of flat batteries are stacked and electrically connected together in series and/or parallel. Another Japanese Laid-Open Patent Publication No. 2004-6141, is also incorporated by reference herein.
As used herein, “battery module” refers to a unit comprising a plurality of connected battery cells, whereas a “battery assembly” refers to a plurality of connected battery modules.
The use and design of battery assemblies having a specific application in vehicles presents a desire for two features. First, it may be desirable that battery assemblies are compact, which may be achieved by reducing the distance between individual flat battery cells as much as possible to reduce the size of the battery modules. Second, the structure of the battery module should not be negatively affected by vibrations. If the battery module is subjected to and affected by vibrations, the stress resulting from such vibrations can in turn affect the joints of the electrode terminals, etc, and thus the durability of the battery. Accordingly, there exists a continuing need for battery modules that are compact in size while maintaining a structure that is unaffected by vibrations.